A typical compression mold for manufacture of fiber-reinforced composite vehicle wheels in accordance with the prior art includes a lower disc mold section affixed to a stationary base, an upper disc mold section coupled to a ram for axial reciprocation with respect to the lower disc mold section, and a plurality of rim mold sections carried by the base for radial reciprocation in a fixed plane toward and away from the axis of the upper and lower disc mold sections. When the rim mold sections and the upper disc mold section are reciprocated to their respective closed positions, opposing surfaces of the several mold sections define a mold cavity for compression-forming an integral vehicle wheel, including a central disc portion for mounting the wheel to a vehicle and an annular rim portion for carrying a vehicle tire. In use, a mold charge of fiber-reinforced composite is placed on the upper face of the lower disc mold section, and the remaining mold sections are closed and maintained under heat and pressure. Mold charge material flows as the mold sections are closed into peripheral portions of the mold cavity. It is difficult to control fiber orientation during flow of material into the cavity edges. In wheels having integral bead-retaining flanges at one or both edges of the rim, absence of fiber orientation control can lead to fatigue crack formation at the juncture of the flange and rim base.
U. S. Pat. No. 4,583,933 assigned to the assignee hereof discloses an improved compression mold for composite wheels in which the rim mold segments are radially reciprocable in a fixed plane, and in which both the upper and lower disc mold segments are axially reciprocable with respect to the rim mold segment plane. The axially reciprocable lower disc mold segment permits fiber-reinforced mold charge material to be placed in the flange-forming portions of the mold cavity prior to closure of the mold segments, as distinguished from urging the mold charge material to flow into the flange-forming sections of the mold cavity as in the previous art. The mold construction so disclosed permits enhanced control of fiber orientation in the rim flange area, with consequent improved reliability and operating life in the resulting wheels. However, the mold disclosed in the noted patent requires construction of a special die to permit reciprocation of the lower mold section.